The NRL will investigate a vile racist slur made against Sydney Roosters star Latrell Mitchell after the Kangaroos centre called out the offender.

Mitchell posted a screenshot on Sunday night of a racial slur made on Facebook, where the offenders claimed they would laugh if his neck was broken.

Mitchell’s post has been shared by fellow indigenous star Joel Thompson, with NRL chief executive Todd Greenberg taking fire at the offender.

“Racism must be called out in all its forms because the standard you walk past is the standard you accept,” Greenberg said.

“I commend Latrell for doing just that. These comments are disgusting and have no place in our game.

“What I love about rugby league is the diverse cultures and backgrounds it brings together. The heritage of our players is what makes our game so special.

“Incidents like this show why our school programs like In League In Harmony and Indigenous rounds are so important to educate the next generation about inclusion.

“There is no place for any sort of abuse on social media towards our players or their families.”

The NRL will investigate if the person behind the comments is a club member, and if he can be barred from attending games.

The Roosters are also well aware of the matter, and are leaving the issue in the hands of the NRL.

Rugby League Players’ Association boss Ian Prendergast also backed the actions of Mitchell and Thompson for taking a stand on the matter.

“We encourage our players to have a voice in terms of telling their stories or about themselves and helping promote the interests of the game generally,” Prendergast told AAP.

“But I think they’ve also got a strong voice in calling out behaviour they think is unacceptable. It can help better protect their fellow players as we’ve seen in recent times.

“Hopefully we see a trend in towards this type of behaviour that is completely unacceptable being called out as well.”